Reproductive cycle and fecundity ofPotimirim glabra(Kingsley, 1954) (Caridea, Atyidae) from a littoral stream

Abstract

The reproductive cycle of Potimirim glabra, especially the female size at sexual maturity, reproductive period and fecundity, was studied at two sites of one of the northern littoral streams in the state of São Paulo, Brazil. Prawns were collected monthly for one year. The minmum size at sexual maturity was estimated from the smallest ovigerous female (cephalothorax length = CL), and the reproductive period was determined monthly by examining the relative frequency of ovigerous females. Size comparisons between sampling sites was carried out using the Mann-Whitney u test. The relationship between environmental factors and reproductive aspects was verified using the Spearman's rank correlation. At Site 1, the collected ovigerous females had a CL mean size of 4.24±0.36 mm (n=481); at Site 2, ovigerous females (n=391) had a CL mean size of 5.48±0.49 mm. The reproductive pattern in Camburi is seasonal, with the highest frequency of ovigerous females in February. The frequency of ovigerous females was positively correlated to organic matter content in the substratum, rainfall and temperature. Increased percentage organic matter may indicate greater food availability whereas higher rainfall increases the velocity of the current, thereby aiding the larvae, which depend on brackish water to complete their development, to reach the estuarine region. The temperature acts on the speed of larval development. At Site 1, the mean fecundity obtained was 202±72.31 eggs (90 females; CL from 2.7 to 4.7mm PL), whereas at Site 2, it was 433.3±120.7 eggs (46 females; CL from 4.0 to 5.5mm PL).

Reproductive biology and population structure of Potimirim brasiliana Villalobos, 1959 (Decapoda, Atyidae) from a littoral fast-flowing stream, São Paulo State, Brazil

“…Determination of the reproductive period was based on the temporal variation in the relative frequency of ovigerous females (Barros & Fontoura, 1996a;Bueno & Shimizu, 2008;Rocha et al, 2010). Minimum size at sexual maturity in females was based on the smallest ovigerous specimen sampled (Barros & Fontoura, 1996a;Lima & Oshiro, 2002;Martínez-Mayen & Román-Contreras, 2005;Hoffmann & Negreiros-Fransozo, 2010). Minimum size at sexual maturity in males could not be determined because all sampled males exhibited a fully developed appendix masculina on the second pleopod.…”

“…The family Atyidae alone comprises approximately 470 species/subspecies of freshwater and anchialine shrimps that inhabit subtropical and tropical ecosystems (e.g., Guo & De Grave, 2004;De Grave et al, 2008;Hoffmann & Negreiros-Fransozo, 2010;De Grave & Fransen, 2011).…”

“…Data on reproductive biology and growth of P. brasiliana (published as P. glabra) are available for populations from the states of Santa Catarina and Sao Paulo (Barros & Fontoura, 1996a;Hoffmann & Negreiros-Fransozo, 2010;Grilli, 2012). In the present paper, we investigate the population structure, reproductive biology and fecundity of & P brasiliana population from the Juréia-Itatins Ecological Station in Peruibe, south-eastern Brazil.…”

Reproductive biology of Argis lar from the East Sea of Korea (Decapoda, Natantia)

“…In addition, we found that the second spawning period was longer than the first, and that more individuals were involved in the second spawning (i.e., in spawning group II). Oviposition in some decapods is known to be controlled not only by endogenous mechanisms but also by favourable environmental conditions (Hoffmann & Negreiros-Fransozo, 2010). Therefore, the second spawning period may be longer than the first because of increased temperatures at that time.…”

“…The reproductive period of caridean shrimps is characterized by the presence of ovigerous females, the frequency of which may vary during different seasons, indicating peaks of reproductive activity for each population, which are reflected in the gonadosomatic indices and larval hatching rates (Sanz, 1987;Hoffmann & Negreiros-Fransozo, 2010). In this study, we found that ovigerous females were present throughout the year, and that there were two main spawning periods, one in the fall to early winter, the other in the late winter to spring; this indicates that A. lar spawns at least twice during the year.…”